Lower Bounds for Off-Chain Protocols: Exploring the Limits of Plasma c
summary
Paper proves a formal impossibility: for any Plasma-style off‑chain ledger with M users (and users only talking to the operator) either the system admits non‑uniquely attributable mass action of size about M/4 with significant probability, or some honest exit must require communicating Omega(M) bits (≈M/4 coins) to the chain. Proof uses an adversary that picks a random subset S, rewinds clients, and an information‑theoretic counting argument about describing random subsets; result is theoretical, not an implementation.
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chapters (19)
- 0:00Intro
- 1:56Off-chain protocols
- 2:52One way to look at the blockchair
- 4:49Idea: relax these requirements a bit
- 7:41What can go wrong if the operator is malicious? Malicious
- 8:23Optimistic vs. pessimistic scenaric
- 9:29Maybe for some applications, weaker guarantees suffice?
- 12:48"Virtual bank" before
- 14:08How does it look like?
- 16:46Two main types of Plasmas
- 19:13"Fungible Plasma" NOCUST or StarkDEX
- 21:06What if there is data unavailability? In Fungible Plasma: Escape from the Plasma ledger before it's too late!
- 21:54This is a problem...
- 23:04Uniquely vs non-uniquely attributable faul
- 24:08Griefing If a fault is non-uniquely attributable then it is not clear who should cover the smart contract fees.
- 25:58Plasma Cash vs. Fungible Plasma non-uniquely
- 29:58The first phase of our attack
- 31:41The second phase
- 35:08Conclusion
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